Stone-dressing machine



March 25 1924.

- L. DOTZER STONE mmssmc, MACHINE Filed me 20 3 Sheets-Sheet 1 March 25,1924. 1,488,235

. DOTZER STONE DRES S I NG MACHINE Filed June 20 1921 5 Sheets-Sheet 2March 25, 11.924.

L. DOTZER STONE DRESSING MACHINE Filed June 20. 1921 3 Sheets-Sheet 5Patented Mar. 25, 1924.

LEONARD DOTZER, OF NEW YORK, N. Y., ASSIGNOR TO WALLACE T. JONES, JR, OF

' BROOKLYN, NEW YORK.

STONE-DRESSING IIIACHINE.

Application filed June 20, 1921. Serial No. 478,810.

T 0 all whom it may concern Be it known that I, LEONARD Do rznn, acitizen of the United States, and a resident of New York, in the countyof New York and State of New York, have invented a certain new anduseful Stone-Dressing Ma chine, of which the following is a description.

My invention relates to machines for what is commonly known as dressingmill stones, and is adapted to dress, in accordance with the particularrequirements thereof, the stones of mills used in grinding orpulverizing material of any kind, such, for example, as cocoa beans,pigments, antimony, copper-scale, grain, cement, ores, inks, etc.

The dressing of a stone comprises the cutting of grooves or cracks inits grinding surface, and generally includes, also, the cutting of thelarger grooves known as fours and the facing of the surface of thestone. Heretofore this has commonly been done manually, by skilledworkmen using a chisel and hammer or a pneumatic chisel. The dressing ofstones in this way is, of course, a slow and expensive process, andoften the results are unsatisfactory due to the unavoidable chipping ofthe stone and beveling of the cracks.

It has heretofore been proposed to employ in stone cracking, poweroperated emery wheels driven by a flexible shaft, but so far as I amaware attempts thus to make the work of cracking the stone lesslaborious have be .H unsuccessful.

The general object of my present invention is to provide a machine whichwill dress stones rapidly, efficiently and automatically, and which maybe adjusted to cutcracks of any desired character corresponding with thenature of the work for which the stones are intended, and also may beused properly to true the face of the stone.

Vith this and other objects in view, which will appear more fullyhereinafter, my in-' vention consists in the novel machine, parts andcombinations of parts described herein and more particularly defined inthe appended claims.

In the accompanying drawing, whichis intended merely to illustrate andnot to limit my invention,

' ig. 1 is a plan view of my stone dressing machine applied to a stonewhich is being dressed.

Fig. 2 is a longitudinal sectional view on the line Ill-II of Fig. 1,the motor being shown in elevation for the purpose of simplicity;

Fig. 3 is a transverse sectional view taken on the line IIIIII of Fig. 2and showing the controlling mechanism for the disk advancing means; 7

Fig. 4 illustrates the belt, drive from the motor shaft to the diskshaft;

Fig. 5 is a plan view of an adjustable supporting plate for the machine;

Fig. 6 is a plan view of the machine (with the motor removed) supportedby a modified formofsupporting plate; and

Fig. 7 shows, in reduced scale, a stone in which both the grooves andthe fours have been cut by my machine.

Referring particularly to Figs. 1 and 2, the supporting plate 10 ispivotally supported at one end by the pedestal 11 which is located atthe center of the stone to be dressed. The other and outer end of theplate 10 is supported by means of the leg 12 which rests upon the outeredge 13 of the stone. This arrangement permits of the radial adjustmentof the supporting plate, and the parts carried thereby, about the centerof the stone as an axis.

Mounted upon the plate 10 adjacent its outer end is a frame 14 upon thetop of which the electric or other motor 15 is supported by the thrustbearing 16. As will be described presently, this motor, in its normaloperation, is adapted to oscillate back and forth in a horizontal planeupon the bearing 16. The vertical spindle 17, which is supported by theframe 14, is located at the axis of oscillation of the motor and isoscillated thvreby. The motor also imparts to the shaft 17 anintermittent downward or advancing movement to which I shall refer morein detail hereinafter. At its lower end the shaft 17 carries the support18 for the sleeve 19 within which is the shaft 19 which carries at itsouter end cutting wheels or disks 20 which may be of any desired numberand dimensions and spaced at any desired distance apart. These disks maybe of any suitable abrasive material, such as emery, carborundum, etc.

The shaft 19 is driven from the motor shaft' 2l-by any suitable means,such, for example, the belt 22 interposed between the drive pulley 23mounted on the motor shaft 21 and the driven pulley 24 mounted upon thedisk shaft 19. Thus the motor 15 spins the disks 20 about their own axisand, through theshaft 17, causes them to partake of a horizontaloscillatory or swinging movement, and an intermittent, downward ordisk-advancing movement. The result is that when properly positioned andadjusted my machine, or more properly the disks 20 of my machine, willautomatically cut in the stone areuate grooves of the desired characterand depth. By properly adjusting the axes about which the disks 20 spinand oscillate, it is apparent that the character of the grooves may bewidely varied. That is, they maybe made of equal depth throughout, orthey may be made of unequaldegth, with the greatest depth either attheir inner extremity or at their outer extremity. Again, they may becut perpendicular to the surface of the stone, or at any other desiredangle thereto.

Before describing the method of operation of my machine any more indetail, I shall now describe the means which I employ for imparting tothe shaft- 17 and thus to the disk shaft 19 and disks 20, the horizontalor oscillatory movement and the intermittent downward or disk-advancingmovement to which I have referred above. v

As above stated, the horizontal oscillatory movement is imparted to theshaft 17 by the motor 15 which, itself, oscillates upon the bearing 16,and to the base of which the shaft 1'? is splined as indicated at 26.The motor may be oscillated or, more accurately speaking, may be causedto oscillate itself in the following manner. The forward end of themotor shaft 21 is provided with a worm 27 which engages with the wormwheel 28 mounted'upon the shaft 29 which is supported by the bracket 30secured to the motor casing. At its lower end the shaft 29 carries thegear 31 which meshes with and drives the gear 32 which in turn drivesthe slotted crank 33. The worm and gears are so proportioned as to drivethe crank 33 at the desired speed relative to the speed of themotorshaft, and, obviously, any other suitably proportioned powertransmitting mechanism may be substituted for the gearing abovedescribed.

The slot 34 in the crank 33 receives the pin 35 which is carried at theouter end of the link 36, the inner end of which is pivoted at 37 to thestationary frame 14. The pin '35 may be retained at any desired positionwithin the slot3 by means of the nut 35. Thus it isap-parent thattherotationxofthe' crank 33; in cooperation with the pivoted link 36,will oscillate the motor upon its thrust bearing 16. The extent oramplit-udeof this oscillation :of the motor and the resultingoscillation of the shafts17 and 19 and the disks 20 depends upon'theposition of the pin 35 in the slot 3st. The center line of theoscillations may be adj List-ed with reference to the center line of themachine by lengthening or shortening the link 36 by means of the turnbuckle 38.

The means which I preferto employ for imparting the intermittentdownward or dislnadvancing movement to the shaft 17 and to the shaft 19and disks 20 which are supported by the shaft17, as follows: Surroundingthe major portion of the shaft 17 is the hollow shaft 39, the exteriorsurface of which is screw-threadedv and is in engagement with thefemale-thread portion 40 of the stationary frame 14:. Relativelongitudinal movement between the shafts 17 and 39 is prevented by somesuch means:

as the abutment 41 of support- 18, and the nut 4-2 which takesion shaft17 adjacent the upper end of shaft 39. Between the abutment all and thelower end of shaft 39 and between the nut 42 and the upper end of shaft39, I preferably place thrust bearings as shown at 43 and a l tofacilitate relatively rotary movement between the shafts 17 and 39. Itis apparentthat the rotation of the threaded shaft 39 in the properdirection within the female threaded portion 40 of the stationary framewill result in the downward movement of the shaft 39 and of-the partscarried thereby, namely, the shaft 17 and the disk-carrying shaft 19 anddisks 20. The belt tighteningdevice 23 is provided to compensate for thevertical move- -ment of the driven pulley 24: of shaft 19 relatively tothe drive pulley 23 of motor shaft 21.

I. effect the above referred-to rotation of the shaft 39 in thefollowing manner: The collar 4-5 is secured to the shaft 17, adjacentitsupper end, by some such means as a set screw t6 2 and This collar isprovided with a lug -17. -Loosely mounted on the shaft 17 adjacent thecollar 45 is a pawl-arm 4-8 which carries at its outer end. a pawl 19,and at its inner end two spaced lugs 50, 51, each provided with. anadjust mentscrew 52, 53, and a lock nut. The pawl 4-9 cooperates withthe ratchet 54 which is secured to or is integral with the shaft 39. Thelug 41-7, as it oscillates with the shaft 17, first strikes the screw 52of lug 50, swinging the arm a3 in a counter-clockwise direction (Fig. 3)and retracting the pawl with relation to the ratchet, and then strikesthe screw 53 of lug 51, swinging the arm 48 in a clockwise direction andadvancing the pawl 49 and causing it to rotate the ratchet 54 and shaft39. This intermittent rotation of the shaft 39 results, of course,-inthe intermittent downward or dislnadvancing movement of the shafts 39,

17 and 19 and the disks 20. The ultimate result is that the disks cutinto the stone a little deeper at V each oscillation. The depths whichthe disks are advanced at each oscillation depend upon the number ofteeth the ratchet 54' advanced at each oscillation and may be regulatedby adj ustment screws 52, 53. f

In order that the grooves cutby the disks may be of the desired dept-hthroughout their length I have so arranged the lugs 47, 50 and 51 thatthe lug 47 does not contact with the screw 53 of lug51 until the diskshave traveled out beyond the periphery of.

the stone. For example, Figs. 1 and 3 represent the disks and associatedparts at the inner limit of their travel. The lug 47 (Fig.

3) has just contacted with the screw 52 and pushed it and the lug 50 andarm48 in a counter-clockwise direction, retracting the pawl 49 a numberof teeth, depending upon the adjustment of screws 52, 53. The disks andtheir associated parts are now ready to start'on their outward travel. jAs they move outwardly the lug 47 moves away from the lug 50 but doesnot. strike the lug 51', or itsiscrew 53, until after the disk s 20 havepassed d of the stone. It then strikes the lug 51 (orscrew 53) and.advances the pawl, ratchet, etc., the predetermined amount.

In conjunction with the mechanism which "I have just describedforadvancing the disks, I provide means for stopping the machineautomatically after the disks have been advanced a predetermined totalamount, or in other words, after the particular series of grooves beingout have been cut to the predetermined depth' These means include anadjustable clip 55'which may be secured by a set screw at any desiredpoint upon the periphery of the ratchet Wheel 54. At.-eachoscillation'of the machine this clip is advanced with the ratchet towardthe lever arm 56 of the electric switch 57 which controls the mot-orcircuit preferably through a magnetically retained time, if a deepercut, is desired than will starting box lever, or the like. Finally the,pin 58 of the clip strikes the lever arm 56 of the switch, opening theswitch and stopping the motor; .The amount of advance of the ratchet andthe disks 20 which will takeplace before'this stoppage occurs, depen'ds,of course, upon the original set-.

ting of the clip 55 on the ratchet wheel;

that is, the" distance originally existing be tween the clip and} theswitch. ,As herein shown, the pin 58. of the clip 55 is in the 7 form ofa vertically'extending'rod which is so: arranged that the switchlevei'garin' will lie in its path even' though the ratchet 54 isconsiderably depressed -Of course the. clip f55 'nia besoarranged thatit will open the switch 57 only as it reaches it the second a stone inwhich result from one complete revolution of the ratchet wheel 54.

The method of operation of my machine is as follows The machine isplaced upon the stone to be dressed, and cutting disks of the desirednumber, size and spacing are secured to the shaft 19. The ratchet isturned manually to place the disks at the proper level for the initialcut. The screws 52, 53 are adjusted for the desired diskadvance for eachoscillation, and the clip 55 is set for the desired total depth of cut.The machine is then started by closing the motor circuit and the disksare causedby the motor to spin, to oscillate and to advance inaccordance with the requirements of the particular job. When the diskshave advanced the required amount, that is, when the grooves have beencut to the required depth, the pin 58 of clip 55 strikes the lever arm56, opens the switch and stops the motor. The operator then adjusts theplate and the parts supported by it upon the stone so that the disks arein the proper position to cut another series of grooves, the ratchetwheel 54 being retracted to place the disksagain at their properstarting level, and the motor is again started. The above describedoperation is repeated until the entire surface of the stone is dressed.V

In addition to cutting the grooves or cracks in the stone, as abovedescribed, my machine may be utilized also to cut the larger and morewidely separated grooves known as the fours, by using suitable cuttingdisks and properly adjusting the machine to providefor grooves of thedesired length and depth. In Fig. 7 I have shown both the grooves 0rcracks C and the fours F have been cut by'my machine.

If it is desired to provide for the adjustment of the operative parts ofmy machine toward and from the center of the stone, this may be done bysubstituting for the supportto be Idressed, a plate such as 10 (Fig. 6)

maybe used, This plate is supported in any suitable manner (as bylegs,not shown) independently ofthe st ne. lVhen it is used the stonemay be supported upon a turn-' table or otherwise arranged so'that itmay be"rotated with reference to the dressing machine, at the completionof each series of lit) cuts, the frame 14 remaining stationary. In otherrespects the machine shown in Fig. 6 is the as that described above.

The advantages of my invention, as above described, will be apparent tothose skilled in the art. They include the production of more regular,keener edges and more efficient grooves than has been possibleheretofore, coupled with the reduction of the labor cost to apractically negligible amount. In the use of my invention only enough ofthe stone is cut out to form the desired grooves, while when the groovesare chiseled, as has been customary heretofore, more of the stone iscracked out than is necessary to produce the cutting edges. My inventiontherefore not only produces more efficient grooves, but in doing so alsoeconomizes on stone.

The only labor required to dress stones when my machines are used isthat of a comparatively unskilled workman who resets the machine eachtime it automatically stops upon the completion of a series of grooves,and this workman can be doing other things between times. Also thelength of time required to dress a stone with the use of my machine isvery much less than that consumed in the old manual process, as willreadily appear. This is of particular importance, not only because ofits saving in labor, but also because usually a mill, representing alarge investment, remains idle while its stones are being dressed.

Many changes may be made in the machine herein described withoutdeparting from the spirit of my invention.

The machine herein disclosed and the modifications herein suggested arenot intended in any way to include all of the embodiments of myinvention as defined in the appended claims, but are intended merely asillustrative embodiments of that invention.

In certain of the claims I have referred to the oscillation of thecutting disks as being substantially parallel to the surface of thestone, and to the advance of those disks as beingsubstantiallyperpendicular to that surface. Of course, if the grooves are cut ofuniform depth throughout their length the oscillation of the disks willhave to be parallel t the stone surface, and if the grooves are cutperpendicularly the advance of the disks will have to be perpendicularto that surface. But since I contemplate using my machine also to cutgrooves of greater depth at one end than at the other, and grooves whichare not exactly perpendicular to the stone surface, I have used theexpressions substantially parallel and substantially perpendicular andintend these expressions to cover the operation of my machineirrespective of the particular character of groove it may be adjusted toout.

1 ,asaase It should be understood, also, that in referring to my machineas a stone dressing machine and to the object it is adapted to dress asa stone, I do not use the Word stone in its ordinary literal sense butintend to cover thereby all milling or similar mem bers which requiredressing whether they be made of stone, metal, or other material. lurthermore, in using the term oscillating as applied to the to-and-fromovement of the disks I do not intend to limit myself to a movement inthe arc of a circle since, as above noted, this movement may be in anydesired curve or in a straight line in any desired direction. r

The terms and expressions which I have employed are used as terms ofdescription and not of limitation, and I have no intention, in the useof such terms and expressions, of excluding any mechanical equivalentsof the features shown and described, or portions thereof, but recognizethat va rious structural modifications are possible within the scope ofthe invention clanned.

hat I claim is: v

1. In a stone dressing machine, a driving shaft, a disk shaft disposedsubstantially parallel to the stone'to be dressed and having one or morecutting disks mounted thereon, power operated means for rotating saiddisk shaft, means operated from said driving shaft for oscillating saiddisk shaft in a plane substantially parallel to the surface of saidstone, and means also operated by said drivingshaft for advancing saiddisk shaft in a direction substantially perpendicular to said surface toincrease the depth of cut of said disks.

2. In a stone dressing machine, a driving shaft, a driven shaft, one ormore cutting disks mounted upon said driven shaft and driven thereby andadapted to contact with the surface of a stone to cut'the same, andmeans operated from said driving shaft for oscillating said driven shaftin a direction substantially parallel to the surface of said stone andfor advancing said driven shaft in a direction substantiallyperpendicular to said surface to increase the depth of cut of saiddisks. 7

3. In a stone dressing machine, a driving shaft, a driven shaft, one ormore cutting disks mounted upon said driven shaft and driven thereby andadapted to contact with the surface of a stone to cut the same, meansoperated from said driving shaft for oscillating said driven shaft ina'direction substantially parallel to the surface of said stone, andmeans operated from said driving shaft and adapted to advance saiddriven shaft at each oscillation thereof, in a direc tion substantiallyperpendicular to said surface, to increase the depth of cut of,said

disks.

4. In a stone dressing machine, a driving shaft, a driven shaft, one ormore cutting lating said driven shaft in a direction substantiallyparallel to the surface of said, stone, means f rad usting the amplltudeof said oscillations, and ieans operable from said driving shaft andadapted to advance said driven shaft at each oscillation thereof 1n adirection substantially perpendicular to said surface to increase thedepth of cut of said disks. r

5. In a stone dressing machine, a power operated shaft, one or morecutting disks mounted thereon and driven therebyv and adapted to contactwith. the surface of a stone to, cut the same, means foraut0maticallyoscillating said shaft and at each oscillation thereof advancing it in adirection substantially perpendicular to said surface to increase thedepth of cut of said disks, and adjustment means for predetermining thedistance said shaftis to be so advanced at each oscillation.

6. In a stone dressing machine, a power operated shaft, one or morecutting disks mounted thereon and driven thereby and adapted to contactwith the surface of a stone to cut the same, means for automaticallyoscillating said shaft and at each oscillation thereof advancing it in adirection substantially perpendicular to said surface to increase thedepth of cut of said disks, and means adapted automatically to stop saidmachine when said shaft has been advanced a predetermined totaldistance.

7. In a stone dressing machine, a power operated shaft, one or'morecutting disks mounted thereon and driven thereby and adapted to contactwith the surface of a stone to cut the same, means for automaticallyoscillating said shaft in a plane substantially parallel to the surfaceof said stone, and means to adjust the amplitude of said oscillations toconform to the size of the stone being dressed.

8. In a stone dressing machine, a power operated shaft, one or morecutting disks mounted thereon and driven thereby and adapted to contactwith the surface of a stone to cut the same, means for automaticallyoscillating said shaft in a plane substantially parallel to the surfaceof said stone, and means for adjusting the center line of saidoscillations with respect to the center line of said machine.

9. In a stone'dressing machine, a power operated shaft, one or morecutting disks mounted thereon and driven thereby and adapted to contactwith the surface of a stone to cut the same, means for automaticallyoscillating said shaft in a plane substantially parallel to the surfaceof said stone, means to adjust the amplitude of said oscillations toconform to the size of the stone being dressed, and means for adjustingthe center line of said oscillations with respect to the center line ofsaid machine.

10. In a stone dressing machine,a power operated shaft, one or morecutting disks mounted thereon and driven thereby and adapted to contactwith the surface of a stone to cut the same, means for automaticallyoscillating said shaft and at each oscillation thereof advancing it in adirection substantially perpendicular to said surface to increase thedepth of cut of said disks, means adapted automatically to stop saidmachine when said shaft has been advanced a predetermined totaldistance, and adjustment means for predetermining said total distance.

11. In a stone dressing machine, a power operated shaft, one or morecutting disks mounted thereon and driven thereby and adapted to contactwith the surface of a stone to cut the same, means for automaticallyoscillating said shaft and at each os cillation thereof advancing it ina direction substantially perpendicular to said surface to increase thedepth of cut of said disks, adjustment means for predetermining thedistance said shaft is to be so advanced at each oscillation, and meansadapted automatically to stop said machine When said shaft has beenadvanced a predetermined total distance.

12. In a stone dressing machine, a poweroperated shaft, one or morecutting disks mounted thereon and driven thereby and adapted to contactwith the surface of a stone to out the same, means for automaticallyoscillating said shaft and at each oscillation thereof advancing it in adirection substantially perpendicular to said surface to increase thedepth ofrcut of said disks, adjustment means for predetermining thedistance said shaft is to be so advanced at each oscillation, meansadapted automatically to stop said machine when said shaft has beenadvanced a predetermined total distance, and adjustment means forpredetermining said total distance.

13. In a stone dressing machine, a power driven and oscillated shaftadapted to carry and drive stone cutting disks, a support for said shaftprovided with a pawl and ratchet mechanism, and means partaking of theoscillatory movement of said shaft for advancing said pawl and ratchetmechanism to impart an advancing movement to said shaft supporting meansand said shaft, at each oscillation thereof.

14. In a stone dressing machine, a frame, a power driven and oscillatedshaft adapted to carry and drive one or more stone cutting disks, asupport for said shaft in screwthreaded engagement with said frame andprovided with ,a ratchet, a pawl, and means partaking of the oscillatorymovement of said shaft for oscillating said pawl and thereby impartingto said ratchet and support a rotary movement, at each oscillation ofsaid shaft, said screw threaded engagement between said support andframe serving to translate said rotary movement into a shaft advancingmovement in a direction substantially perpendicular to the surface ofthe stone being dressed.

15. In a stone dressing machine, a frame, a power driven and oscillatedshaft adapted to carry and drive one or more stone cutting disks, asupport for said shaft in serewthreaded engagement with said frame andprovided with a ratchet, a pawl, means partaking of the oscillatorymovement of said shaft for oscillating said pawl and thereby impartingto said ratchet and support a 1'0- tary movement, at each oscillation ofsaid shaft, said screw threaded engagement between said support andframe serving to translate said rotary movement into a shaft advancmgmovement in a directlon substantially perpendicular to the surface ofthe support for said shaft provided with a pawl and ratchet mechanism,means partaking of the oscillatory movement of said shaft foradvancingsaid pawl and ratchet mechanism to impart an advancing movement to saidshaft supporting means and said shaft, at each oscillation thereof, andmeans operated by said pawl and ratchet mechanism and adapted to stopsaid machine when said pawl and ratchetmechanism has been advanced apredetermined total distance. i

' LEONARD DOTZER;

